Minor ObjC header updates.

webrtc/base/objc/RTCLogging.mm

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import "RTCLogging.h"
 
 #include "webrtc/base/logging.h"
 
 rtc::LoggingSeverity RTCGetNativeLoggingSeverity(RTCLoggingSeverity severity) {
   switch (severity) {
-    case kRTCLoggingSeverityVerbose:
+    case RTCLoggingSeverityVerbose:
       return rtc::LS_VERBOSE;
-    case kRTCLoggingSeverityInfo:
+    case RTCLoggingSeverityInfo:
       return rtc::LS_INFO;
-    case kRTCLoggingSeverityWarning:
+    case RTCLoggingSeverityWarning:
       return rtc::LS_WARNING;
-    case kRTCLoggingSeverityError:
+    case RTCLoggingSeverityError:
       return rtc::LS_ERROR;
   }
 }
 
 void RTCLogEx(RTCLoggingSeverity severity, NSString* log_string) {
   if (log_string.length) {
     const char* utf8_string = log_string.UTF8String;
     LOG_V(RTCGetNativeLoggingSeverity(severity)) << utf8_string;
   }
 }
 
 void RTCSetMinDebugLogLevel(RTCLoggingSeverity severity) {
   rtc::LogMessage::LogToDebug(RTCGetNativeLoggingSeverity(severity));
 }
 
 NSString* RTCFileName(const char* file_path) {
   NSString* ns_file_path =
       [[NSString alloc] initWithBytesNoCopy:const_cast<char*>(file_path)
                                      length:strlen(file_path)
                                    encoding:NSUTF8StringEncoding
                                freeWhenDone:NO];
   return ns_file_path.lastPathComponent;
 }